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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Sustainable Biofuels and Co-products Research » Research » Publications at this Location » Publication #428110
Research Project: Marketable Products from Thermochemical Biorefineries

Location: Sustainable Biofuels and Co-products Research

Title: Hydrothermal liquefaction of waste ice cream for biocrude and hydrochar utilization

Author
item Elkasabi, Yaseen
item Garcia, Rafael
item Plumier, Benjamin
item Jones, Kerby
item Mullen, Charles

Submitted to: Energy and Fuels
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2026
Publication Date: 3/25/2026
Citation: Elkasabi, Y.M., Garcia, R.A., Plumier, B.M., Jones, K.C., Mullen, C.A. 2026. Hydrothermal liquefaction of waste ice cream for biocrude and hydrochar utilization. Energy and Fuels. https://doi.org/10.1021/acs.energyfuels.5c06560.
DOI: https://doi.org/10.1021/acs.energyfuels.5c06560

Interpretive Summary: Ice cream companies produce large amounts of waste ice cream, due to problems with the ice cream product. Examples problems with ice cream include contamination and product failing to meet quality specifications. As such, these producers are looking for ways to reuse the waste into something valuable, instead of throwing the product away. This work explores ways to chemically change the ice cream into compounds similar to jet fuel and solids similar to charcoal for soil improvement. This work will be useful to the dairy industry that need to reduce losses due to lost product.

Technical Abstract: Dairy product manufacturers contend with large volumes of waste ice cream (WIC) that cannot be sold due to allergen contamination and/or failed product specifications. Simultaneously, there is significant need and opportunity to thermochemically upgrade biomass into higher-value products, such as sustainable aviation fuel and biochar. As a two-pronged solution to both issues, we studied the hydrothermal liquefaction (HTL) of WIC, where our goals were to 1) optimize process conditions for producing value-added products and 2) determine the distribution of proteinaceous nitrogen into specific products. Two types of melted WIC (standard; high-fat content) underwent HTL for 1 hr at varying temperatures (210 – 330 oC), catalysts and additives (Ru/C, Pt/C, Pd/C, Na2CO3), and gaseous environments (N2, H2). HTL at 210 oC without any additives produced the highest yields of hydrochar, compared to other conditions. Mass yield of hydrochar directly correlated with yield of nitrogen in the hydrochar. Addition of sodium carbonate doubled the yield of biocrude and increased the efficiency of nitrogen partitioning into the hydrochar. Under reducing conditions (Ru/C at 210 oC under hydrogen), HTL produced the highest yields of paraffinic biocrude. However, catalytic hydrogenation tended to increase unwanted partitioning of the proteinaceous nitrogen into the biocrude. Catalytic hydrotreatment of the biocrude produced products from both decarboxylation and hydrodeoxygenation pathways. To maximize yield and minimize nitrogen in biocrude, a two-step hydrotreatment process is recommended by first treating at 210 oC using 2 wt% Na2CO3, whereby a subsequent catalytic hydrotreatment on only the oil (330 oC and above) will convert free fatty acids into paraffin hydrocarbons.